Common Dolphin

Delphinus delphis

Identification at a glance

  • Dark above, pale green/beige/yellow below (depending on the light)
  • Numbers vary from 2-3 up to 300 hundred
  • Size from 1.9m-2.5m with males generally larger
  • short beak, although longer than the bottlenose dolphin

Range

Warm-temperate and tropical waters, including the Atlantic, Pacific and Indian Oceans, the Caribbean, Mediterranean, Black and Red seas.

Habitat

Short-beaked dophins are common along shelf edges and in areas with sharp bottom relief such as seamounts and escarpments

Behaviour

Diet – small fish such as mackerel, anchovies, lanternfish and sprats, squid and octopus.

Short-beaked common dolphins are very sociable, usually found in groups of hundreds or thousands of others, eating and travelling together. Sometimes they can be seen with other cetaceans, including pilot whales, or bow-riding on other baleen whales. They sometimes bow ride on boats, and if one dolphin is sick, others in the group may hold it up with their fins so that it can survive. Babies are born live and stay close to their mother for six months, at which point they start to catch their own food.

Fun fact! Even though these dolphins are less common than bottlenosed dolphins, these are the ones more likely to be depicted in Greek and Roman pictures and mosaics.

Threats

Like all cetaceans, common dolphins are threatened by entanglement in fishing gear (by-catch) which means they either drown or get taken onto the fishing boats, changes caused by climate change (such as having to find food in new areas), being hit by ships, pollution, oil and gas development and habitat degradation. Some countries, including Japan, also fish dolphins commercially.

Threat level

Whilst in general they are categorised as of Least Concern, some populations, such as the one in the Mediterranean, are protected by the Convention on the Conservation of Migratory Species of Wild Animals. The regional listing means that this particular population is in danger of extinction. In general they are also covered by the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas and the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area.